5DMZ

Structure of human Bub1 kinase domain phosphorylated at Ser969

Summary for 5DMZ

• Entry DOI: 10.2210/pdb5dmz/pdb
• Descriptor: Mitotic checkpoint serine/threonine-protein kinase BUB1, ADENOSINE-5'-DIPHOSPHATE, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: kinase, phosphorylation, transferase
• Biological source: Homo sapiens (Human)
• Cellular location: Nucleus: O43683
• Total number of polymer chains: 2
• Total formula weight: 84752.11

Authors

Breit, C.,Weir, J.R.,Musacchio, A. (deposition date: 2015-09-09, release date: 2015-12-16, Last modification date: 2024-01-10)

Primary citation

Breit, C.,Bange, T.,Petrovic, A.,Weir, J.R.,Muller, F.,Vogt, D.,Musacchio, A.
Role of Intrinsic and Extrinsic Factors in the Regulation of the Mitotic Checkpoint Kinase Bub1.
Plos One, 10:e0144673-e0144673, 2015

PubMed Abstract: The spindle assembly checkpoint (SAC) monitors microtubule attachment to kinetochores to ensure accurate sister chromatid segregation during mitosis. The SAC members Bub1 and BubR1 are paralogs that underwent significant functional specializations during evolution. We report an in-depth characterization of the kinase domains of Bub1 and BubR1. BubR1 kinase domain binds nucleotides but is unable to deliver catalytic activity in vitro. Conversely, Bub1 is an active kinase regulated by intra-molecular phosphorylation at the P+1 loop. The crystal structure of the phosphorylated Bub1 kinase domain illustrates a hitherto unknown conformation of the P+1 loop docked into the active site of the Bub1 kinase. Both Bub1 and BubR1 bind Bub3 constitutively. A hydrodynamic characterization of Bub1:Bub3 and BubR1:Bub3 demonstrates both complexes to have 1:1 stoichiometry, with no additional oligomerization. Conversely, Bub1:Bub3 and BubR1:Bub3 combine to form a heterotetramer. Neither BubR1:Bub3 nor Knl1, the kinetochore receptor of Bub1:Bub3, modulate the kinase activity of Bub1 in vitro, suggesting autonomous regulation of the Bub1 kinase domain. We complement our study with an analysis of the Bub1 substrates. Our results contribute to the mechanistic characterization of a crucial cell cycle checkpoint.

PubMed: 26658523
DOI: 10.1371/journal.pone.0144673

Experimental method

X-RAY DIFFRACTION (2.4 Å)